Phase 2a safety and immunogenicity testing of DNA and recombinant modified vaccinia ankara virus vaccines expressing virus-like particles oleh Goepfert P, Elizaga M, Montefiori D, Hural J, DeRosa S, Tomaras G, Seaton K, Sato A, Ouedraogo L, Donastorg Y, Cardinali M, Lama J, Baden L, Keefer M, McElrath J, Kalams S, Robinson H